In the wake of the financial crisis, an increasing number of thoughtful analysts are arguing that inequality threatens growth. Yet the biggest effects of rising inequality are probably not on growth itself, but on the ability of growth to translate into rising living standards, opportunity and security for the broad middle class.

And the most likely reason for these negative effects is that rising inequality distorts our politics — leading to weaker representation for the middle class and increased gridlock — so that sensible policy choices are more difficult.

Let’s start with the facts. Over the last generation, less equal countries like the U.S. do not seem to have grown consistently faster. If rising inequality doesn’t lead to higher growth, then, by definition, it lowers middle-class income gains. In the United States, overall productivity has grown relatively strongly. The rewards of this growth, however, have gone mostly to the top.

Yet even this understates the problem. In addition to income growth, Americans also care about opportunity and security. And both have stalled or declined despite growing productivity. Long-term upward mobility has stagnated as inequality has grown. Intergenerational mobility — how kids do relative to their parents — is lower in the United States than in almost any other rich nation.

At the same time, economic security has eroded. Private health insurance is less common, income instability has risen, people’s private safety net of wealth has been decimated, and Americans are less well prepared for retirement.

These are not insoluble problems, and recent research and historical experience strongly indicate that tackling them would accelerate, not hinder, overall growth. As we have argued in a recent report titled, “Prosperity Economics,” such win-win policies include immediate investments in productive physical capital like infrastructure (which would put people back to work and increase future growth) as well long-term investment in pre-K and college education.

They would also include measures to tackle health costs and give workers (particularly in low-wage sectors) greater bargaining power and more professionalized career paths. And they would require a serious assault on special deals for industries like the financial and energy sectors that impose risks and costs onto our society for which they don’t have to pay.

The problem of course is the politics, and here we come to most fundamental means by which rising inequality has affected the economic lives of most Americans — for the worse.

As growing inequality has translated into rising political inequality, it has been harder and harder to act on sensible prescriptions that would increase middle-class living standards, security and opportunity, as well as overall economic growth. Ensuring that today’s economic winners don’t dominate our political process may be the most important way to improve the quality of economic life for all Americans.